The goal of this proposal is to identify and characterize novel oncogenes expressed in patients with acute myeloid leukemia (AML). The design of this proposal is to position the candidate for an independent career in basic cancer research, with a focus on leukemia, in an academic environment. Working in Dr. Channing Der's laboratory at the University of North Carolina at Chapel Hill has provided an excellent foundation for this career. With a little more guidance from Dr. Der, the candidate will utilize the outstanding resources that Dr. Der's laboratory and the University of North Carolina at Chapel Hill provide, in order to solidify the scientific basis for an independent career in research. The first two specific aims of this research proposal focus on characterizing a novel activator of Ras, RasGRP4, identified by the candidate in a screen for novel oncogenes in AML. RasGRP4 is primarily expressed in myeloid cells suggesting it has a specific role in these cells. Targeted disruption of the gene for RasGRP4 in mice will be utilized to characterize the normal function of RasGRP4. The development of the hematopoietic system of these mice will be analyzed along with signal transduction pathways that may utilize RasGRP4. These studies represent an excellent opportunity to expand the candidate's technical repertoire (e.g., animal model development and analyses of primary hematopoietic cells), by combining the resources provided by the UNC Chapel Hill animal model facility and Dr. Der's expertise on Ras signal transduction. The last aim of this proposal, which will be initiated in the independent phase of the award, is to perform additional screens for oncogenes in AML. AML formation requires two classes of mutations: one that induces cell proliferation and survival, and one that inhibits differentiation. AML1-Eto and CBFb-MYH11, two common oncogenes in AML, are not sufficient to induce leukemia. This proposal describes experiments to identify required mutations, expressed in AML patients whose leukemic cells harbor these fusion proteins, that cooperate with these oncogenes and also to identify members of both classes of AML oncogenes. This will provide an opportunity to expand and improve strategies aimed at identifying novel oncogenes in AML. In summary, this proposal provides an excellent opportunity for the candidate to complete his training to become an independent researcher.